| <html lang="en"> |
| <head> |
| <title>Input/Output - Debugging with GDB</title> |
| <meta http-equiv="Content-Type" content="text/html"> |
| <meta name="description" content="Debugging with GDB"> |
| <meta name="generator" content="makeinfo 4.13"> |
| <link title="Top" rel="start" href="index.html#Top"> |
| <link rel="up" href="Running.html#Running" title="Running"> |
| <link rel="prev" href="Working-Directory.html#Working-Directory" title="Working Directory"> |
| <link rel="next" href="Attach.html#Attach" title="Attach"> |
| <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> |
| <!-- |
| Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, |
| 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
| Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being ``Free Software'' and ``Free Software Needs |
| Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,'' |
| and with the Back-Cover Texts as in (a) below. |
| |
| (a) The FSF's Back-Cover Text is: ``You are free to copy and modify |
| this GNU Manual. Buying copies from GNU Press supports the FSF in |
| developing GNU and promoting software freedom.''--> |
| <meta http-equiv="Content-Style-Type" content="text/css"> |
| <style type="text/css"><!-- |
| pre.display { font-family:inherit } |
| pre.format { font-family:inherit } |
| pre.smalldisplay { font-family:inherit; font-size:smaller } |
| pre.smallformat { font-family:inherit; font-size:smaller } |
| pre.smallexample { font-size:smaller } |
| pre.smalllisp { font-size:smaller } |
| span.sc { font-variant:small-caps } |
| span.roman { font-family:serif; font-weight:normal; } |
| span.sansserif { font-family:sans-serif; font-weight:normal; } |
| --></style> |
| <link rel="stylesheet" type="text/css" href="../cs.css"> |
| </head> |
| <body> |
| <div class="node"> |
| <a name="Input%2fOutput"></a> |
| <a name="Input_002fOutput"></a> |
| <p> |
| Next: <a rel="next" accesskey="n" href="Attach.html#Attach">Attach</a>, |
| Previous: <a rel="previous" accesskey="p" href="Working-Directory.html#Working-Directory">Working Directory</a>, |
| Up: <a rel="up" accesskey="u" href="Running.html#Running">Running</a> |
| <hr> |
| </div> |
| |
| <h3 class="section">4.6 Your Program's Input and Output</h3> |
| |
| <p><a name="index-redirection-123"></a><a name="index-i_002fo-124"></a><a name="index-terminal-125"></a>By default, the program you run under <span class="sc">gdb</span> does input and output to |
| the same terminal that <span class="sc">gdb</span> uses. <span class="sc">gdb</span> switches the terminal |
| to its own terminal modes to interact with you, but it records the terminal |
| modes your program was using and switches back to them when you continue |
| running your program. |
| |
| |
| <a name="index-info-terminal-126"></a> |
| <dl><dt><code>info terminal</code><dd>Displays information recorded by <span class="sc">gdb</span> about the terminal modes your |
| program is using. |
| </dl> |
| |
| <p>You can redirect your program's input and/or output using shell |
| redirection with the <code>run</code> command. For example, |
| |
| <pre class="smallexample"> run > outfile |
| </pre> |
| <p class="noindent">starts your program, diverting its output to the file <samp><span class="file">outfile</span></samp>. |
| |
| <p><a name="index-tty-127"></a><a name="index-controlling-terminal-128"></a>Another way to specify where your program should do input and output is |
| with the <code>tty</code> command. This command accepts a file name as |
| argument, and causes this file to be the default for future <code>run</code> |
| commands. It also resets the controlling terminal for the child |
| process, for future <code>run</code> commands. For example, |
| |
| <pre class="smallexample"> tty /dev/ttyb |
| </pre> |
| <p class="noindent">directs that processes started with subsequent <code>run</code> commands |
| default to do input and output on the terminal <samp><span class="file">/dev/ttyb</span></samp> and have |
| that as their controlling terminal. |
| |
| <p>An explicit redirection in <code>run</code> overrides the <code>tty</code> command's |
| effect on the input/output device, but not its effect on the controlling |
| terminal. |
| |
| <p>When you use the <code>tty</code> command or redirect input in the <code>run</code> |
| command, only the input <em>for your program</em> is affected. The input |
| for <span class="sc">gdb</span> still comes from your terminal. <code>tty</code> is an alias |
| for <code>set inferior-tty</code>. |
| |
| <p><a name="index-inferior-tty-129"></a><a name="index-set-inferior-controlling-terminal-130"></a>You can use the <code>show inferior-tty</code> command to tell <span class="sc">gdb</span> to |
| display the name of the terminal that will be used for future runs of your |
| program. |
| |
| <dl> |
| <dt><code>set inferior-tty /dev/ttyb</code><dd><a name="index-set-inferior_002dtty-131"></a>Set the tty for the program being debugged to /dev/ttyb. |
| |
| <br><dt><code>show inferior-tty</code><dd><a name="index-show-inferior_002dtty-132"></a>Show the current tty for the program being debugged. |
| </dl> |
| |
| </body></html> |
| |
